Download SUNA Manual

SUNA Manual
For SUNA running firmware version 2.5 or later
SAT-DN-00628, Rev. E, 2014-Dec-01
Satlantic LP
3481 North Marginal Road
Halifax, Nova Scotia B3K 5X8
Canada
+1 902 492 4780
[email protected]
www.satlantic.com
CONFIDENTIAL
This document contains information proprietary to Satlantic or to a third party to which Satlantic may have legal
obligation to protect such information from unauthorized disclosure, use or duplication. Any disclosure, use or
duplication of this document in whole or in part, or of any of the information contained herein, for any purpose
other than the specific purpose for which it was disclosed is expressly prohibited except as Satlantic may
otherwise agree to in writing.
© 2013, Satlantic LP, All rights reserved
SUNA Manual
For SUNA running firmware version 2.5 or later
Table of Contents
1. About This Manual..............................................................................................5
2. Start-up Guides...................................................................................................6
2.1 Start-up Guide for Terminal Interface..........................................................6
2.2 Start-up Guide for SDI-12 Interface.............................................................7
2.3 Start-up Guide for Analog Output.................................................................8
3. The SUNA Sensor..............................................................................................9
3.1 Introduction and Background.......................................................................9
3.2 Specifications...............................................................................................9
3.2.1 Build Variants........................................................................................9
3.2.2 Electrical Specification........................................................................13
3.2.3 Performance Specifications................................................................14
3.3 Operating Principles...................................................................................17
3.3.1 Absorbance Spectroscopy..................................................................17
3.3.2 Nitrate Concentration..........................................................................18
3.3.3 Interferences and Mitigation................................................................18
4. Terminal Interface of the SUNA.......................................................................20
4.1 Sensor Operating States............................................................................20
4.2 Command Line Interface............................................................................20
4.2.1 Status and Maintenance Commands.................................................21
4.2.2 File Commands...................................................................................22
4.2.3 Configuration Commands...................................................................23
4.2.4 Polled Mode Commands.....................................................................38
4.2.5 SDI-12 Mode Commands...................................................................38
4.2.6 Analog Output.....................................................................................42
5. Configuration Parameters in Context...............................................................46
5.1 Build Configuration.....................................................................................46
5.2 Input / Output Configuration.......................................................................47
5.3 Data Acquisition Configuration...................................................................48
5.3.1 Continuous and Fixed-time Operating Mode......................................48
5.3.2 Periodic Operating Mode....................................................................49
5.3.3 Polled Operating Mode.......................................................................49
5.3.4 SDI-12 Operating Mode......................................................................50
5.4 Data Processing Configuration..................................................................51
5.4.1 Basic Data Processing........................................................................51
5.4.2 Special Case: Bromide Tracing..........................................................51
5.4.3 Special Case: Highly Absorbing Water...............................................51
6. Use Scenarios...................................................................................................53
6.1 Profiling.......................................................................................................53
6.1.1 Objectives and Considerations...........................................................53
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SUNA Manual
For SUNA running firmware version 2.5 or later
6.1.2 Example..............................................................................................53
6.2 Moored........................................................................................................54
6.2.1 Objectives and Considerations...........................................................54
6.2.2 Example..............................................................................................55
7. SUNA Frame Definitions...................................................................................57
7.1 Frames with Synchronization Headers......................................................57
7.2 APF Frame.................................................................................................58
7.3 MBARI Frame.............................................................................................60
8. SUNA Calibration File.......................................................................................61
8.1 File Name...................................................................................................61
8.2 File Format..................................................................................................61
8.3 File Interpretation........................................................................................61
9. Firmware Upgrade............................................................................................62
9.1 Firmware Upgrade Using SUNACom.........................................................62
9.2 Firmware Upgrade Using the Terminal Interface.......................................62
10. Troubleshooting..............................................................................................63
10.1 Sensor Is Not Responsive........................................................................63
10.2 Sensor Output Is Unexpected..................................................................64
11. Accessories.....................................................................................................65
11.1 Foul Guard................................................................................................65
11.2 Wiper........................................................................................................65
11.3 Flow Cell...................................................................................................67
12. Maintenance...................................................................................................68
13. Safety And Hazards........................................................................................69
13.1 Pressure Hazard.......................................................................................69
13.2 Electrical Hazard......................................................................................69
13.3 Deployment and Recovery Safety............................................................69
14. Warranty.........................................................................................................70
14.1 Warranty Period.......................................................................................70
14.2 Restrictions...............................................................................................70
14.3 Provisions.................................................................................................70
14.4 Returns.....................................................................................................70
14.5 Liability......................................................................................................70
15. Contact Information........................................................................................71
16. Revision History..............................................................................................72
Index of Tables
Table 1: Sensor dimensions, basic options............................................................9
Table 2: Optional features....................................................................................10
Table 3: SUNA dimensions depending on options...............................................10
Table 4: Power requirements................................................................................13
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SUNA Manual
For SUNA running firmware version 2.5 or later
Table 5: Electrical pin assignments and descriptions..........................................14
Table 6: General performance specifications.......................................................15
Table 7: Accuracy specification for nitrate concentrations...................................15
Table 8: Precision specification for nitrate concentrations...................................16
Table 9: Limit of Detection and Limit of Quantification........................................16
Table 10: File access commands.........................................................................22
Table 11: Build configuration parameters.............................................................26
Table 12: Input / output configuration parameters...............................................29
Table 13: Data acquisition configuration parameters...........................................34
Table 14: Data processing configuration parameters..........................................37
Table 15: Combinations of data processing configuration parameters...............37
Table 16: SUNA build variants.............................................................................46
Table 17: Data acquisition configuration parameters by operating mode...........50
Table 18: Data processing configuration parameters in use case context..........52
Table 19: Configuration parameters illustrating a profiling deployment...............54
Table 20: Configuration parameters illustrating a moored deployment...............56
Table 21: Synchronization header frame definitions............................................58
Table 22: APF data frame definition.....................................................................59
Table 23: MBARI data frame definition................................................................60
Index of Illustrations
Illustration 1: Drawing of Standard SUNA with 10 mm path length.....................11
Illustration 2: Drawing of Standard SUNA with 5 mm path length........................11
Illustration 3: Drawing of Standard SUNA with 10 mm path length and wiper.....12
Illustration 4: Drawing of Standard SUNA with 5 mm path length and wiper.......12
Illustration 5: SUNA SubConn MCBH8MNM bulkhead connector face view.......13
Illustration 6: Foul Guard......................................................................................64
Illustration 7: SUNA with integrated wiper............................................................65
Illustration 8: Space requirements for the integrated wiper..................................65
Illustration 9: Flow Cell..........................................................................................66
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SUNA Manual
For SUNA running firmware version 2.5 or later
1. About This Manual
1. About This Manual
The SUNA is a versatile sensor that can operate in diverse environments. It is adaptable
to a wide variety of deployment scenarios and supports multiple interfaces. This manual
provides guidance on how to properly deploy the sensor and on how to interact with it.
Before operating the sensor, understand all warnings and cautions cited in section 13.
Safety And Hazards.
Section 3. The SUNA Sensor gives performance specifications, sensor dimensions, and
explains the measurement technology.
The SUNACom software provides a graphical user interface to facilitate working with the
sensor. It supports sensor configuration, system testing, data management, and data
re-processing. SUNACom has a separate user manual, which is available on the
installation CD and from within the SUNACom application via context sensitive help.
SUNACom does not address the requirements for all deployment scenarios, particularly
those related to integrated systems. For this reason, the complete firmware interface is
specified in Section 4. Terminal Interface of the SUNA. Explanations on how to start
when working in this environment are found in Section 2.1 Start-up Guide for Terminal
Interface.
The decision on how to configure the sensor is driven by the type of deployment.
Section 5. Configuration Parameters in Context provides an explanation of configuration
parameters. Section 6. Use Scenarios discusses configuration choices for some types
of deployments, and Section 7. SUNA Frame Definitions defines the output data.
Components supporting the deployment of the SUNA are specified in Section 11.
Accessories.
Some deployments benefit from components that can be added to the SUNA.
The SUNA is a versatile sensor and research is ongoing to expand its performance and
use. Support of new features can be coded into future SUNA firmware versions. Section
9. Firmware Upgrade provides instructions on how to install such a new firmware.
Explanation and remediation for some unexpected behavior of the SUNA are addressed
in Section 10. Troubleshooting, and guidance on handling is provided in Section 12.
Maintenance.
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SUNA Manual
For SUNA running firmware version 2.5 or later
2. Start-up Guides
2. Start-up Guides
Refer to the Quick Start section of the SUNACom User manual available on your
installation CD or bundled with the SUNACom software to test basic operation and
configuration. The following start-up guides will guide you through the process of
connecting to interfaces not available via SUNACom.
2.1 Start-up Guide for Terminal Interface
Terminal Emulator
The end user can interface with the SUNA by using terminal emulator software that can
connect to a serial com port. Some computers have pre-installed terminal emulators
(e.g., HyperTerm in some Microsoft Windows operating systems). Other terminal
emulators are, e.g., Putty, Tera Term, Bray's Terminal. This guide assumes that the
user is familiar with operating a terminal emulator.
Cable
In order to use the terminal interface, connect the sensor's serial cable to a com port of
the computer, and power the sensor with 8–18 VDC (8–15 VDC for SUNA with an
integrated wiper), capable of providing a current of at least 1 A.
Serial Interface
The SUNA communicates via serial port, using the RS-232 protocol at 8 bit, no parity, 1
stop bit and no flow control. The baud rate is factory set to 57600. If this baud rate does
not work, try the other possible baud rates (9600, 19200, 38400, 115200) or use
SUNACom to scan for the current baud rate.
Command Line
When power is applied to the SUNA, output and behavior depend on the current sensor
configuration. In all instances the user can bring the sensor to the command line by
repeatedly sending the $-character to the sensor.
The sensor indicates that it is accepting commands by outputting the SUNA> prompt. All
commands available at the command line are given in section 4.2 Command Line
Interface.
An example command is selftest. It turns on all subsystems and briefly reports their
status.
Using the get opermode command will report the current operation mode. Consult
section 5.3 Data Acquisition Configuration to understand the different operating modes,
and use the set opermode command if another operating mode is needed. Use the
get cfg command for the current sensor configuration.
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SUNA Manual
For SUNA running firmware version 2.5 or later
2. Start-up Guides
2.2 Start-up Guide for SDI-12 Interface
The SUNA has an optional SDI-12 interface.
Use SUNACom or the terminal interface to find out if the sensor is equipped with the
SDI-12 Interface.
Within SUNACom verify the SDI-12 is listed as one of the options under the Operational
Mode of the SUNA Settings display. See the SUNACom user manual for details.
At the terminal interface, use the get sdi12brd command. The response will be either
Available or Missing.
Start SDI-12 Operation
SUNA sensors are not factory set to operate in SDI-12 mode. To operate the sensor as
a SDI-12 device, it first has to be configured to do so.
In SUNACom select SDI-12 as the operating mode under the SUNA Settings display
and Upload. See the SUNACom user manual for details.
At the terminal interface, use the set opermode SDI12 command.
Data Processing
Before deployment, the user should confirm that the data processing configuration is
suitable for the expected deployment. See section 5.4 Data Processing Configuration for
details.
Deployment
After the sensor has been configured to run in SDI-12 operation mode, and processing
has been configured, the sensor can be rebooted or power cycled. At this point, the
sensor will respond to SDI-12 commands. For supported SDI-12 commands, see
section 4.2.5 SDI-12 Mode Commands.
End SDI-12 Deployment
In order to bring the sensor out of SDI-12 mode, either use SUNACom or the terminal
interface.
In SUNACom select another operating mode under the SUNA Settings display and
Upload. See the SUNACom user manual for details.
In the latter case, sending the $ character brings the sensor to the command line, and
allows the user to switch to another operating mode via the set opermode command.
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SUNA Manual
For SUNA running firmware version 2.5 or later
2. Start-up Guides
2.3 Start-up Guide for Analog Output
The SUNA has an optional analog output system.
The end user can determine if the sensor is equipped for analog output either via the
SUNACom software or the terminal interface (see section 2.1 Start-up Guide for
Terminal Interfaceand section 4. Terminal Interface of the SUNA).
In SUNACom the DAC calibration function will be visible under the Advanced, Sensor
menu item if this function is available.
At the terminal interface, use the get analgbrd command. The response will be either
Available or Missing.
Interpreting Analog Output
When analog output is available, the sensor automatically generates output voltage and
current.
The sensor generates an output voltage in the 0 to 4.096 V and an output current in the
4 to 20 mA range. The lower range of the respective output interval corresponds to the
DAC Minimum and the upper range of the interval corresponds to the DAC Maximum
configuration parameter.
Both the DAC minimum and DAC maximum values can be modified, either via
SUNACom or via the terminal interface, to tune the output range to the expected nitrate
concentration range.
While the output voltage and current generated by the sensor are highly accurate,
losses may occur across cables that are used. For details on calibration and data
interpretation, see section 4.2.6 Analog Output.
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
3. The SUNA Sensor
3.1 Introduction and Background
The SUNA (Submersible Ultraviolet Nitrate Analyzer ) is a chemical-free nitrate sensor.
It is based on the ISUS (In Situ Ultraviolet Spectroscopy) technology developed at
MBARI (cf. Kenneth S. Johnson, Luke J. Coletti, In situ ultraviolet spectrophotometry for
high resolution and long-term monitoring of nitrate, bromide and bisulfide in the ocean,
Deep-Sea Research I 49 (2002) 1291–1305).
3.2 Specifications
3.2.1 Build Variants
The SUNA housing is made from acetal, and is suitable for deployments of up to 500 m
depth, or 100 m depth with the optional integrated wiper.
Table 1: Sensor dimensions, basic options.
Dimension
Basic Variant
Material
Acetal / Titanium
Depth Rating
500 m
100 m (integrated wiper)
Diameter
63 mm
Length
(without connector and anode)
567 mm
UV Deuterium Lamp
900 h lifetime
Path length
10 mm
Displacement
1749 cm³
Weight
2.5 kg
Electrical connector
SubConn MCBH8MNM
Storage temperature
–20 to +50 C
Operating temperature
--2 to +35 C
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Optional features and accessories change some sensor dimensions, as shown below.
Table 2: Optional features
Feature / Accessory
Comment
Reduced path length
5 mm
Calibration
Normal: NO3 only
Optional: NO3 & seawater
Analog output
Optional
SDI-12 interface
Optional
Internal data logging
Optional 2 GB (or larger) solid state
Scheduling
Optional
USB connectivity
Optional
Active fouling control
Integrated wiper
Passive fouling control Copper fouling guard
Sampling control
Flow through cell
Power supply
Battery pack
Table 3: SUNA dimensions depending on options.
Options
Length Displacement Weight
Standard SUNA, basic variant
567 mm
1749 cm³
2.5 kg
Standard SUNA, 5 mm path length
562 mm
1745 cm³
2.5 kg
Standard SUNA, integrated wiper
588 mm
2092 cm³
3.1 kg
Standard SUNA, 5 mm path length, integrated wiper 583 mm
2084 cm³
3.1 kg
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Illustration 1: Drawing of Standard SUNA with 10 mm path length.
Illustration 2: Drawing of Standard SUNA with 5 mm path length.
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Illustration 3: Drawing of Standard SUNA with 10 mm path length and wiper.
Illustration 4: Drawing of Standard SUNA with 5 mm path length and wiper.
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
3.2.2 Electrical Specification
The SUNA requires power in the 8–18 VDC range with a supply current of 1 A (8–15
VDC for SUNA with an integrated wiper). Power consumption depends on the operating
state. During data acquisition, it is typically 7.5 W (±20%). In standby, at the command
prompt, the current draw is around 20 mA.
Polled and APF operating modes will time out after a configurable time of inactivity,
bringing the SUNA processor into a low power state with a consumption below 3 mA. In
fixed-time operation and between periodic operation event, power control is handed to a
supervisor circuit, which reduces power consumption to less than 30 μA.
Table 4: Power requirements
State
Voltage
Current
Supervised Sleep
Processor Sleep
Standby
< 30 μA
< 3 mA
8–18 VDC
(8–15 VDC with integrated wiper)
Sampling
~20 mA at 12 V
~625 mA at 12 V (nominal)
The SUNA connector is a SubConn MCBH8MNM. With a face view numbering as in the
following illustration, the pin assignments are listed in the following tables.
Illustration 5: SUNA SubConn MCBH8MNM bulkhead connector face view.
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Table 5: Electrical pin assignments and descriptions.
Pin
Standard
Optional
USB / Analog Out
1
VIN
VIN
2
GND
GND
3
–
USB V+
4
–
SDI-12
5
TXD
TXD / D+
6
RXD
RXD / D–
7
–
VOUT
8
–
IOUT
Pin Assignment
Description
VIN
External DC power supply, 8–18 VDC or 8–15 VDC
GND
Power supply return, signal ground
USB V+
USB 5V power
SDI-12
Serial data interface at 1200 baud
TXD
RS-232 transmit (from SUNA)
RXD
RS-232 receive (to SUNA)
D+
USB D+
D–
USB D–
VOUT
Analog volt output
IOUT
Analog current output
3.2.3 Performance Specifications
The SUNA sensor is designed to measure the concentration of nitrate ions in water. The
measurement result is in molar concentration, units of micro molar (μM). For user
convenience, this concentration is converted into units of milligram per liter (mg/l), and
output in digital form as well. 1 μM nitrogen corresponds to 0.014007 mg/l nitrate.
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Table 6: General performance specifications
Measurement
Nitrate concentration [NO3-]
Thermal compensation (optional)
0–35ºC
Salinity compensation (optional)
0–40 psu
Optical path length
10 mm, optional 5 mm
Spectral range
190–370 nm
The performance of the sensor depends on a number of factors. One factor is the
optical path length, normally at 10 mm, optionally at 5 mm. The optical path length
influences the concentration measurement range covered by the sensor, and the
accuracy of the results. Another factor is the type of calibration: a sensor specific
calibrations are more accurate than a class-based calibration. The former uses
extinction coefficients that are measured using the sensor itself; the latter uses
averaged extinction coefficients, that were obtained from many sensors.
Table 7: Accuracy specification for nitrate concentrations
Concentration Range
10 mm Path Length
5 mm Path Length
For regular seawater and freshwater calibrations
up to 1000 μM
2 μM or 10%
4 μM or 10%
up to 2000 μM
2 μM or 15%
4 μM or 15%
up to 3000 μM
2 μM or 20%
4 μM or 15%
up to 4000 μM
out-of-range
4 μM or 15%
For class-based freshwater calibrations
up to 1000 μM
2.5 μM or 20%
4.5 μM or 20%
up to 2000 μM
2.5 μM or 25%
4.5 μM or 25%
up to 3000 μM
2.5 μM or 30%
4.5 μM or 25%
up to 4000 μM
out-of-range
4.5 μM or 25%
The precision of the sensor depends on its data processing configuration (see section
5.4 Data Processing Configuration). In oceanographic or estuarine settings, data must
be processed for seawater, in freshwater settings data processing is ideally selected to
be for freshwater. In seawater settings, the sensor precision can be brought into the
freshwater precision by post-processing in SUNACom with Temperature-SalinityCorrection applied.
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Table 8: Precision specification for nitrate concentrations
Processing configuration
Freshwater or Seawater
with T-S-Correction
Seawater
[0–40 psu]
Short-term precision [at 3σ]
0.3 μM
2.4 μM
Drift [per hour of lamp time]
<0.3 μM
<1.0 μM
The limit of detection is defined as the nitrate concentration that has a value of 3 times
the standard deviation of the blank nitrate concentration. As such, it is 3 times the
standard deviation as measured for the sensor precision, which depends on the
processing mode.
The limit of quantification specifies the limit at which two samples can be reasonably
distinguished. Typically, it is 10 times the standard deviation of the blank nitrate
concentration.
Table 9: Limit of Detection and Limit of Quantification
Processing configuration
Freshwater or Seawater
with T-S-Correction
Seawater
[0–40 psu]
Limit of detection [LOD]
0.3 μM
2.4 μM
Limit of quantification [LOQ]
1.0 μM
8.0 μM
Natural waters may contain a mixture of interfering species that are typically hard to
delineate. The impact of interfering species on the measured nitrate concentration was
determined under laboratory conditions. The specification covers two classes of
interfering species: suspended particulate matter (Turbidity) and colored dissolved
organic matter (CDOM). The impact is independent of the optical path length, from
theoretical considerations as well as experimentally confirmed. However, the SUNA can
only operate up to absorbances of approximately 1.5. This limit is typically reached at
625 NTU (Nephelometric Turbidity Units) for 10 mm path length, or at 1250 NTU for 5
mm path length. Naturally occurring CDOM concentrations stay within the operating
range of the SUNA.
The following substances were uses as proxies for turbidity:
ARD Arizona Road Dust
Kaolin Kaolin Powder
TiO2 Titanium Dioxide
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Turbidity
Sample
NTU
per mg/l
Absorbance at
225 nm (10 mm)
per mg/l
NO3 shift μM
in freshwater
per mg/l
NO3 shift μM
in seawater
per mg/l
ARD
1.25
0.0016
<-0.002
0.01
Kaolin
1.5
0.0085
<0.001
0.02
TiO2
15.0
0.0090
<0.001
<0.001
The following samples, obtained from the International Humic Substances Society, were
used as proxies for CDOM:
PLFA Pony Lake Fulvic Acid – Reference (1R109F)
SRFA Suwannee River Fulvic Acid – Standard (1S101F)
PPHA Pahokee Peat Humic Acid – Reference (1R103H-2)
CDOM
Sample
QSD
per mg/l
Absorbance at
225 nm (10 mm)
per mg/l
NO3 shift μM
in freshwater
per mg/l
NO3 shift μM
in seawater
per mg/l
PLFA
N/A
0.017
0.4
0.6
SRFA
N/A
0.027
<0.1
<0.1
PPHA
42
0.003
<0.01
<0.1
An interfering species generates a spurious nitrate concentration when the spectral
characteristics of the interfering species resembles that of nitrate. Typically, an RMSE
value that is more than a few times the RMSE of a pure nitrate sample should be taken
as an indication that interfering species are impacting the measurement. The RMSE
value is the square root of the mean of the sum of the squared differences between the
measured and the fitted absorbance; it provides a measure for the quality of the fit.
Independent measurements of turbidity and CDOM, as well as an analysis of the
absorption spectrum, can refine the impact analysis.
3.3 Operating Principles
3.3.1 Absorbance Spectroscopy
The SUNA measures the concentration of dissolved nitrate in water. The sensor
illuminates the water sample with its deuterium UV light source, and measures the
throughput using its photo-spectrometer. The difference between this measurement and
a prior baseline reference measurement of pure water constitutes an absorption
spectrum.
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Absorbance characteristics of natural water components are provided in the sensor
calibration file. The Beer-Lambert law for multiple absorbers establishes the relationship
between the total measured absorbance and the concentrations of individual
components. Based on this relationship, the sensor obtains a best estimate for the
nitrate concentration using multi-variable linear regression.
The approach described above was initially developed at MBARI (cf. Kenneth S.
Johnson, Luke J. Coletti, In situ ultraviolet spectrophotometry for high resolution and
long-term monitoring of nitrate, bromide and bisulfide in the ocean, Deep-Sea Research
I 49 (2002) 1291–1305) and the technology then transferred to Satlantic.
3.3.2 Nitrate Concentration
Nitrate processing uses the 217–240 nm wavelength interval, which contains
approximately 35 spectrometer channels. For each channel, the absorbance is
calculated, and decomposed into individual absorbers using the MBARI method.
The precision of the nitrate concentration depends on the number of absorbers into
which the measured absorbance is decomposed. Thus, in freshwater deployments, the
number of concentrations to be fitted should be set to 1.
High absorbance conditions introduce inaccuracies into the nitrate concentrations.
Therefore, channels with an absorbance greater than 1.3 are excluded from processing.
If less than about 10 channels remain, the sensor is unable to determine a nitrate
concentration, and the measurement is no longer valid (out-of-bounds). Users can
overturn the standard setting and increase the absorbance cutoff, obtaining reduced
accuracy nitrate concentrations at higher absorbances. There is, however, a limit at
around 2.5 absorbance units, when nitrate concentrations can no longer be determined.
3.3.3 Interferences and Mitigation
The quality of the nitrate measurements can be impacted in a number of ways. This
impact has been quantified (see section 3.2.3 Performance Specifications) for some
significant interfering influences. Here, interferences are explained, and mitigation
options are explored.
Sample temperature: Seawater is known to have a temperature-dependent absorption.
If this effect is not taken into account, a bias and/or imprecision are introduced to the
reported nitrate concentration.
This effect can be mitigated by providing sample temperature and salinity to the nitrate
calculation, either in real-time (supported in APF mode) or in SUNACom postprocessing (collection of spectra and accompanying temperature and salinity data is
required). Temperature-salinity correction follows the approach developed at MBARI (cf.
Carole M. Sakamoto, Kenneth S. Johnson, Luke J. Coletti, Improved algorithm for the
computation of nitrate concentrations in seawater using an in situ ultraviolet
spectrophotometer, Limnol. Oceanogr.: Methods 7, 2009, 132–143).
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SUNA Manual
For SUNA running firmware version 2.5 or later
3. The SUNA Sensor
Uncharacterized species in sample: A number of substances occurring in natural
water absorb in the UV spectral range where nitrate absorbs. Usually, the spectral
signature of those substances differs from that of nitrate. However, certain combinations
of water constituents may cause a bias in the calculated nitrate concentrations.
If significant concentrations of interfering species are suspected, sporadic chemical
analysis of water samples allows quantification and correction for the optical
interference.
Sensor drift: Over time, lamp output and throughput of optical components exhibit drift.
This drift translates into a drift in the measured nitrate concentrations.
A regular update of the reference (baseline) spectrum minimizes drift.
Lamp temperature: The lamp output depends on its temperature. Thus, the reference
(baseline) spectrum is ideally collected under conditions that mimic deployment
conditions.
If deployment temperatures are expected to vary by more than 10 °C, a temperature
characterization and subsequent data correction may be attempted.
Optically dense constituents: The sensor performance is compromised in optically
dense conditions, which transmit less light than necessary for the regression analysis.
With increasing optical density, the quality of the measurement (signal-to-noise)
decreases. Accuracy and precision of the nitrate concentrations decrease with
decreasing data quality, until the data are essentially random (or are reported as out-of
range, depending on sensor configuration).
The sensor can be configured to respond to optically dense conditions by repeating the
measurement with an increased spectrometer exposure time, thereby extending the
operating range of the sensor.
High optical densities are often caused by CDOM or turbidity in the water sample. It has
been found that the CDOM concentration in natural waters does not cause optical
extinction. On the other hand, highly turbid waters can cause such high absorption that
the SUNA is not able to measure nitrate. The operation limit for the 10 mm path length
variant is 625 NTU, and for the 5 mm variant it is 1250 NTU.
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4. Terminal Interface of the SUNA
4. Terminal Interface of the SUNA
4.1 Sensor Operating States
At power-up, the SUNA's micro-controller starts the firmware. After initialization, it
retrieves the current settings, and enters its operating mode.
Within each operating mode, the firmware is in one of three states:
standby,
data acquisition,
command interface,
where the transition between the states is controlled by the firmware or driven by user or
controller input.
In standby, the sensor can be at different levels of power consumption. In periodic and
APF mode, the sensor achieves the lowest level between data acquisition events,
whereas in polled mode, the power level is a bit higher, and in SDI-12 mode, the power
level is identical to the one when the sensor is at the command line.
The user can interrupt the SUNA's regular operation in order to enter the command line.
Data Acquisition to Command Interface
Sending a $ character (possible multiple times) will bring the sensor to the command
line. The command line reports via the SUNA> prompt that it is ready to receive
commands.
Command Interface to Data Acquisition
The command line is terminated via the exit or the reboot command.
Data Acquisition to Standby
Only polled and APF modes have explicit commands (SLEEP and SLP, respectively) to
send the SUNA to standby mode.
In periodic mode, the sensor alternates between standby and data acquisition.
Standby to Data Acquisition
Any input will cause the SUNA to come out of its standby state. Then, it waits for 15
seconds for the $ input character to enter the command line, before returning to the
standby state. When entering standby, the sensor requires approximately 15 seconds to
completely discharge its internal circuitry. Any attempt to bring the sensor out of its
standby state occurring within this 15 second period can lead to undefined behaviour.
4.2 Command Line Interface
Communication with the SUNA is conducted via RS-232 or USB connection. The sensor
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4. Terminal Interface of the SUNA
checks for availability of a USB connection, and if present, uses a USB virtual com port
for input and output. Otherwise, the sensor communicates via RS-232.
Commands can be broadly grouped into the following categories:
1.
2.
3.
4.
5.
6.
Status and Maintenance
File Management
Query and Modify Configuration
Polled Mode Commands
APF Mode Commands
SDI-12 Mode Commands
4.2.1 Status and Maintenance Commands
Selftest
The selftest checks operation of sensor components, performs measurements, and
outputs the measurement results.
The last output line will be $Ok if all components performed according to expectations,
or $Error if one or more of the components failed the test. If a component did not
perform as expected, the output line of that component is terminated by an exclamation
mark (!), making it easier to locate the problem.
Get Clock and Set Clock
The get clock command outputs the time of the internal sensor clock. The time is
factory set to UTC.
The set clock YYYY/MM/DD hh:mm:ss command sets the sensor clock to the
specified value.
Used Lamp Time
The firmware keeps track of the total on-time of the lamp, and outputs the number of
seconds via the get lamptime command.
Wiper Test
The firmware provides the special swipewiper command to run the wiper one
time.
DAC Low and DAC High
These commands are only available for SUNAs that have an analog output system.
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4. Terminal Interface of the SUNA
The DAC Low command will generate the lowest analog output that is possible, and the
DAC High command will generate the highest analog output that is possible.
For details on how to make use of this feature, see section 4.2.6 Analog Output.
Upgrade
The firmware exits into the boot loader.
The boot loader allows installing of a new firmware onto the nitrate sensor. See section
9. Firmware Upgrade for details.
Reboot
This command causes the firmware to restart. It is equivalent to performing a power
cycle.
Exit
The command line exits, and data acquisition as configured in the operation mode
restarts. If the baud rate was changed in the current command line session, the sensor
will reboot in order to re-initialize with the new baud rate.
4.2.2 File Commands
File commands give access to data log, message log, and calibration files. All file
commands follow the syntax <Command> <FileType> [<FileName>]. Data and
message log files are an optional feature. Use the selftest command to see if the sensor
has an internal file system, and if so, the space that is available.
File types are CAL for calibration files, LOG for system log message files, and DATA for
files containing logged measurement data.
Table 10: File access commands
Command
CAL
LOG
DATA
Comment
List
+
+
+
Output a list of all files of the specified type
Output
+
+
+
Output the content of the specified file.
Recommended only for small ASCII files.
The command cannot be interrupted.
Send
+
+
+
XMODEM transfer of file from sensor
Delete
+
+
+
Delete specified file from disk. Irreversible.
Receive
+
XMODEM transfer of file to sensor
The sensor can have many calibration files. The user can query the name of the
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4. Terminal Interface of the SUNA
currently active file via the get activecalfile command. The active file cannot be
deleted from the sensor. When a calibration file is received by the sensor, it is made
active. The user can change the active file by the set activecalfile calfilename command.
4.2.3 Configuration Commands
Configuration commands allow the user to query and modify configuration parameters.
The commands follow the syntax
get --<short name>
set --<short name> <value>
setrange --<short name> <value>,<value>
Below is a list of all configuration parameters with a brief explanation. Each subsection
finishes with a table containing the parameters, the range of accepted values, and the
short name for accessing the parameter using the above commands.
The setrange command only applies to the two pairs of wavelength values.
Build Configuration
All build parameters are for information only, and cannot be modified.
Sensor Type
The Sensor Type is SUNA.
Sensor Version
The Sensor Version is V2.
Serial Number
The Serial Number is factory set.
Sensor Brand
The Sensor Brand is Satlantic.
Super Capacitors
The super capacitors are either Available or Missing.
During start-up, the capacitors are charged to provide brief internal power in the event of
a sudden power loss. Internal backup power allows the sensor to shut down into a safe
state.
The disadvantage of super capacitors is an increased total power consumption.
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PCB Supervisor
The PCB supervisor circuit is either Available or Missing.
Sensors are optionally equipped with the PCB supervisor, which allows the sensor to
enter power saving mode.
USB Communication
The USB communication is either Available or Missing.
Sensors are optionally equipped with USB communication. Sensors can always
communicate via RS-232. If USB is available and plugged in, communication switches
to USB.
Relay Module
The relay module is Missing.
This feature is only available in the Deep SUNA.
SDI-12 Interface
The SDI-12 interface is either Available or Missing.
Sensors are optionally equipped with the SDI-12 interface.
Analog Output
The analog output system is either Available or Missing.
Sensors are optionally equipped with analog output system.
Internal Data Logging
Internal data logging is either Available or Missing.
Sensors are optionally equipped with memory for internal data logging.
APF Interface and Temperature-Salinity Correction
The APF interface and temperature-salinity correction is Missing.
This feature is only available in the Deep SUNA.
Scheduling
The scheduling capability is either Available or Missing.
Sensors are optionally capable to run on a configured schedule.
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4. Terminal Interface of the SUNA
Optical Path Length
The optical path length is 5mm or 10mm.
Integrated Wiper
The integrated wiper is Available or Missing.
When a wiper has been integrated into the sensor, control of the wiper operation is
enabled.
External Power Port
The external power port is Missing.
An external power port may be supported in future SUNA versions.
Addresses of Temperature Sensors
The addresses of the three SUNA internal temperature sensors are factory configured,
and provided for troubleshooting.
Spectrometer Serial Number
The spectrometer serial number is factory configured.
Lamp Serial Number
The lamp serial number is factory configured.
Lamp Use Power
The power used by the sensor when the lamp is turned on in units of milliwatt [mW]. It is
measured during sensor assembly, and serves as a reference point for the firmware to
ascertain that the lamp is operating properly. It also allows to estimate the sensor's
power consumption.
Custom ID
The Custom Identification string allows operators to assign their own identification to a
SUNA. The string can be up to 15 ASCII characters long.
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4. Terminal Interface of the SUNA
Table 11: Build configuration parameters
Parameter
Possible Values
Short Name
Sensor Type
SUNA
senstype
Sensor Version
V2
sensvers
Serial Number
1–9999
serialno
Sensor Brand
Satlantic
thebrand
Super Capacitors
Available, Missing
suprcaps
PCB Supervisor
Available, Missing
pwrsvisr
USB Communication
Available, Missing
usbswtch
Relay Module
Missing
relaybrd
SDI-12 Interface
Available, Missing
sdi12brd
Analog Output
Available, Missing
analgbrd
Internal Data Logging
Available, Missing
intdatlg
APF Interface
Missing
apfiface
Scheduling
Available, Missing
schdling
Optical Path Length
5mm, 10mm
pathlgth
Integrated Wiper
Available, Missing
intwiper
External Power Port
Missing
extpport
Address of lamp temperature
sensor
owiretlp
Address of spectrometer
temperature sensor
owiretsp
Address of housing
temperature sensor
owireths
Spectrometer Serial Number
zspec_sn
Lamp Serial Number
fiberlsn
Lamp Use Power [mW]
lmpusepw
Custom ID
String, up to 15 characters
Input and Output Configuration
Baud Rate
The baud rate is one of 9600, 19200, 38400, 57600, or 115200.
A changed baud rate takes effect after the next power-up or reboot.
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Message Level
The message level is one of Error, Warn, Info, Debug, Trace.
Messages are sent to the output stream and are also saved in a message log file.
Message File Size
The message file size is in the 0 to 65 MB range, and initially set to 2 MB.
Setting the file size to zero turns off logging of messages to file.
Data File Size
The data file size is in the 1 to 65 MB range, and initially set to 2 MB.
This value applies only if the data file type is set to Continuous. Daily and per-acquisition
files will contain as much data as is generated during the day or the particular
acquisition.
Output Frame Type / Logging Frame Type
The frame type is one of None, APF, MBARI, Full_ASCII, Full_Binary, Reduced_Binary,
Concentration.
If set to None, no frame data will be written to serial output / data log file, respectively.
For reprocessing of data, Full_ASCII or Full_Binary frames are necessary. Reduced
binary and APF frames allow reprocessing for seawater deployments. APF frames only
allow reprocessing of data that were collected with the integration time adjustment
turned off.
Output Dark Frame / Logging Dark Frame
Dark frames output and logging is either Output or Suppress.
This configuration flag is provided in case when dark frames are not required or desired.
Log File Type
The data log file type is one of Acquisition, Continuous, or Daily.
Data log files names have a single letter (A, C, or D) followed by a 7-digit number,
followed by a 3-letter extension (csv for ASCII, bin for binary data).
Acquisition based data files are started new whenever power is cycled. (But see the
following setting: Acquisition File Duration.)
Continuous data log files are appended to until the Data File Size is reached. Then, the
file number is incremented, and data are added to the next file.
Daily data log files contain all data that are collected within a 24 hour period. The 7-digit
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number is made up of 4-digit for the year and 3-digits for the day-of-year (1 to 365 or
366 for leap years).
Acquisition File Duration
The Acquisition File Duration is set to 60 minutes. This setting is only used if the Log
File Type is set to Acquisition.
The duration can be in the range from 0 to 1440 minutes (one full day). It specifies the
time interval over which data from subsequent power-cycle events are logged to the
same file.
A value of zero forces the creation of a new data log file with every power cycle, while a
value of e.g., 120 collects the data from all acquisition events that occur within 120
minutes into a single file.
When using acquisition based data log files with a high frequency of acquisition events
(e.g., multiple events per hour) over an extended deployment duration, the total number
of files can reach tens of thousands of files. Such a number of files will slow down SUNA
internal data logging.
If daily of continuous log files are not an option, the use of the acquisition file duration
will ensure the number of files stays small.
DAC Minimum / Maximum Nitrate
The DAC minimum nitrate value is initially set to -5 µM, the DAC maximum nitrate value
is set to 100 µM.
These values effect the output generated by the optional analog output system. See
section 4.2.6 Analog Output for details.
Dat Wavelength Low / High
The data wavelength values are set to 217 and 250.
These wavelength define the channels that are included in the APF frame.
SDI-12 Address
The SDI-12 address is factory set to the numerical value 48 (ASCII character '0').
This address is used by an SDI-12 controller when interfacing with a SUNA in SDI-12
operating mode. See section Error: Reference source not found Error: Reference
source not found for details.
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4. Terminal Interface of the SUNA
Table 12: Input / output configuration parameters
Parameter
Possible Values
Default Value Short Name
Baud Rate
9600, 19200, 38400, 57600, 115200 57600
baudrate
Message Level
Error, Warn, Info, Debug
Info
msglevel
Message File Size [MB]
0–65
2
msgfsize
Date File Size [MB]
1–65
5
datfsize
Output Frame Type
Full_ASCII, Full_Binary,
Reduced_Binary, Concentration,
APF, MBARI, None
Full_ASCII
outfrtyp
Full_ASCII
logfrtyp
Output Dark Frame
Output, Suppress
Output
outdrkfr
Logging Dark Frame
Output, Suppress
Output
logdrkfr
Log File Type
Acquisition, Continuous, Daily
Acquisition
logftype
Acquisition file duration [m] 0–1440
60
afiledur
DAC Minimum Nitrate
-5.0
dcmonno3
DAC Maximum Nitrate
100.0
dcmaxno3
210–350
217
wdat_low
Data wavelength high [nm] 210–350
250
wdat_hgh
Logging Frame Type
Data wavelength low [nm]
wdatboth
For the setrange command, use:
SDI 12 Address
48–57 (ascii characters 0–9 )
48 (ascii 0)
sdi12add
Data Acquisition Configuration
Operation Mode
The operation mode is Continuous, Fixedtime, Periodic, Polled, APF, or SDI12.
In Continuous mode the sensor starts to acquire data as soon as initialization is
complete and countdown has expired. Data acquisition proceeds, depending on the
Operation Control setting, either in a sample based (1 dark sample, then Light Samples,
Dark Samples, Light Samples, ...) or time based (1 dark sample, then Light Duration,
Dark Duration, Light Duration) infinite cycle.
In Fixedtime mode, the sensor behaves as in Continuous mode, but terminates after a
maximum of Fixed Time Duration seconds.
In Periodic mode, the sensor acquires data in regular periods, and collects data,
depending on the Operation Control setting, either a fixed number of light samples
(Periodic Samples) or for a fixed time (Periodic Duration).
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IIn Polled mode, the sensor stays in low power sleep, to acquire data only after woken
up by activity on the RS-232 line and then receiving a command (“Start” for indefinite or
“Measure n” for a fixed number of measurements).
In SDI-12 mode, the sensor operates as a SDI-12 device.
Operation Control
The operation control is Duration or Samples based.
Operation control applies to Continuous, Fixed time, and Periodic mode. Either of these
operating modes is further controlled by additional parameters, and Operation Control
determines which parameters apply.
Countdown
The countdown is measured in units of seconds, and initially set to 15.
The countdown is used in Continuous and Fixedtime operation modes.
Fixed Time Duration
The fixed time duration is measured in units of seconds, and can take any positive
number up to and including 1000000.
Periodic Interval
The periodic interval is restricted to a subset of values that divide the day into integer
parts: 1m, 2m, 5m, 6m, 10m, 15m, 20m, 30m, 1h, 2h, 3h, 4h, 6h, 8h, 12h, 24h.
Periodic Offset
The periodic offset is measured in seconds.
Whereas the periodic interval establishes a grid of acquisition times, the offset locates
the grid relative to the start of the day (hour 0).
Note: There is a side effect when an external device needs to run prior to data
acquisition.
Periodic Duration
The periodic duration is measured in seconds.
This parameter is used when Operation Control is set to Duration.
Periodic Samples
The periodic samples are measured in number of light frames.
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This parameter is used when Operation Control is set to Samples.
Polled Timeout
The polled timeout is measured in seconds.
It determines for how long the firmware will wait for a command upon wake-up before
returning to low power standby. A value of zero means there is no timeout.
APF Timeout
The APF timeout is only available in Deep SUNA sensors.
Skip Sleep At Startup
This setting is either On or Off.
If this setting is On, the sensor will not enter the low-power state in polled mode when
first powered up. This flag allows for faster sensor response.
Lamp Stabilization Time
The lamp stabilization time is in units of 1/10 of a second.
After the lamp has ignited, a short time is required to stabilize the lamp output. Typically,
lamps can be used 500 ms after being switched on. This parameter is provided to adjust
the stabilization time.
Lamp Switch-Off Temperature
The lamp switch off temperature is set to 35 C. The lamp should not operate at
temperatures above 35 C.
When the lamp exceeds the switch-off temperature, the sensor overrides the configured
(continuous and fixedtime operation) or enforces (polled and periodic operation) a lightto-dark cycle. Upon reaching the switch-off temperature, initially five cycles of 5-light to
5-dark samples are acquired, and after those, the cycle ratio drops to 1-light to 10-dark
samples. As soon as the lamp temperature has dropped below the switch-off
temperature, the configured acquisition cycle resumes.
If the sensor is deployed in a warm environment, and data acquisition is only sporadic,
please consult with Satlantic on ways to safely changing this configuration.
Spectrometer Integration Period
The spectrometer integration period is factory set.
The integration period should be as large as possible, to obtain a good signal; the
integration period must not be so large as to cause saturation of the signal.
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4. Terminal Interface of the SUNA
The spectrometer integration time should not be changed, because the SUNA is
calibrated for the factory configured value.
Dark Averages and Light Averages
The spectrometer can perform internal averaging. Internal averaging reduces the noise
of a measurement at the expense of a reduced sampling rate. However, the sampling
rate is higher using internal averaging when compared to averaging the samples after
separate collection.
Another advantage of internal averaging is the reduction in the amount of data
generated.
Dark Samples and Light Samples
These parameters are used when Operation Control is set to Samples.
Dark and light samples are used in Continuous and Fixedtime mode, and control the
lamp off/on cycle.
Dark Duration and Light Duration
These parameters are used when Operation Control is set to Duration.
Dark and light duration are used in Continuous and Fixedtime mode, and control the
lamp off/on cycle.
External Device
The external device is None or Wiper.
If the external device is set to Wiper, power will be applied whenever a data collection
begins. Thus, there will be a single wipe at the beginning of a continuous data
acquisition, a single swipe at each collection event in periodic mode, or a single swipe
for each collection command in polled or SDI-12 mode.
External Device Pre-run Time
The external device pre-run time can be set to a value between 0 and 200 seconds.
This is the time that the sensor waits to acquire data after applying power to the external
device. The purpose of this configuration parameter is to let the external device
complete its action without interfering with the sensor's measurements.
External Device On During Acquisition
The external device on during acquisition can be set to On or Off.
This configuration parameter allows the sensor to control if the external device is to
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continue operating during the sensor's data acquisition.
External Device Minimum Interval
The external device minimum interval is a value between 0 and 1440 minutes (one day).
This configuration parameter limits the frequency of the operation of the external device.
At each data acquisition event when the device might be run, the SUNA compares the
current time against the most recent time the device was run. Only if more than the
configured minimum interval has passed, the device will be operated.
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4. Terminal Interface of the SUNA
Table 13: Data acquisition configuration parameters
Parameter
Possible Values
Default Value
Short Name
Operation Mode
Continuous, Fixedtime, Periodic,
Polled, SDI12
Fixedtime
opermode
Operation Control
Duration, Samples
Samples
operctrl
Countdown [s]
0–3600
3
countdwn
Fixed Time Duration [s]
1–1000000
10
fixddura
Periodic Interval
1m, 2m, 5m, 6m, 10m, 15m, 20m,
30m, 1h, 2h, 3h, 4h, 6h, 8h, 12h, 24h
1h
perdival
Periodic Offset [s]
any value
0
perdoffs
Periodic Duration [s]
0–255
10
perddura
Periodic Samples
0–255
10
perdsmpl
Polled Timeout [s]
0–65535
10
polltout
APF Timeout [h]
0–100
10
apfatoff
Skip Sleep At Startup
On, Off
Off
skpsleep
Lamp Stabil. Time [ds]
0–255
5
stbltime
Lamp Switch-Off Temp.
*
35
lamptoff
Spectrometer
Integration Period [ms]
5–60000
N/A
spintper
Dark Averages
1–200
1
drkavers
Light Averages
1–200
1
lgtavers
Dark Samples
1–65535
1
drksmpls
Light Samples
1–65535
10
lgtsmpls
Dark Duration [s]
1–65535
10
drkdurat
Light Duration [s]
1–65535
120
lgtdurat
External Device
None, Wiper
None
exdevtyp
0
exdevpre
Ex. Dev. Pre-run time [s] 0–120
Ex. Dev. During Acq.
On, Off
Off
exdevrun
Ex. Dev. Min. Interval
0–1440
60
exdvival
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4. Terminal Interface of the SUNA
Data Processing Configuration
Processing Wavelength Interval
The processing (also called fitting) interval is normally from 217 to 240 nm.
Changing the fitting interval should be done with caution; an unsuitable fitting interval
generates invalid results.
Concentrations to Fit
The number of concentrations to be used for processing is 1, 2, or 3.
Freshwater calibrated sensors only use 1 concentration; saltwater calibrated sensors
can be made to act like freshwater sensor by setting concentrations to fit to 1. Normally,
saltwater calibrated sensors use 3 concentrations.
Baseline Order
The baseline order is fixed to 1.
Historically, different baseline orders were available. However, there is currently no need
to change the baseline order.
Dark Correction Method
The dark correction method is one of SpecAverage or SWAverage.
The purpose of dark correction is to subtract the temperature dependent dark baseline
from the measurement. When using SpecAverage, a dark spectrum is measured by
either closing the shutter (of present) or switching off the lamp. Using the SWAverage
works if seawater or bromide cause extinction below 200 nm, and the measurement in
that wavelength range is used as a proxy for the dark baseline.
Temperature Compensation
The temperature compensation flag is On or Off.
Real-time processing temperature compensation only works for saltwater calibrated
sensors running in APF mode. The current temperature and salinity values must be
provided via the CTD command. This setting will be ignored if the sensor is not able to
perform this task.
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Salinity Fitting
The salinity fitting flag is On or Off.
Salinity fitting can only be switched off in saltwater calibrated sensors running in APF
mode. The current temperature and salinity values must be provided via the CTD
command. This setting will be ignored if the sensor is not able to perform this task.
Bromide Tracing
The bromide tracing flag is On or Off.
Freshwater calibrated sensors, or saltwater calibrated sensors set to operate as
freshwater sensors (Concentrations to Fit set to 1) can be used to detect bromide, at an
expense of the sensor's nitrate accuracy.
Absorbance Cutoff
The absorbance cutoff is a value between 0.01 and 10.0. It is normally set to 1.3.
Whenever the absorbance of a channel exceeds the specified absorbance cutoff, that
channel is excluded from processing. Setting the cutoff to the maximum value of 10.0
will guarantee that all channels will be included in processing.
Integration Time Adjustment
Integration time adjustment can be Off, On, or Persistent.
When set to On or Persistent, in low transmittance conditions, the sensor multiplies the
normal integration time by the Integration Time Step. When the transmittance increases
later on, the integration time reverts to the normal value.
When set to Persistent, the current Integration Time Factor is kept at power-down to be
used at the next power-up event. Otherwise, the sensor starts with the normal
integration time.
Integration Time Factor
The integration time factor is initially set to 1.
When integration time adjustment is On or Persistent, the integration time factor can be
greater than 1. Currently, only a value of 1 or 20 is permitted.
Integration Time Step
The integration time step is set to 20. It should not be changed.
Integration Time Maximum Factor
The integration time maximum factor is set to 20. It should not be changed.
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4. Terminal Interface of the SUNA
Table 14: Data processing configuration parameters
Parameter
Possible Values
Default Value
Short Name
210–350
217
wfit_low
Fit wavelength high [nm] 210–350
240
wfit_hgh
Fit wavelength low [nm]
wdatboth
For the setrange command, use:
1 or 3
fitconcs
1
1
bl_order
Dark Correction Method SpecAverage, SWAverage
SpecAverage
drkcormt
Concentrations to fit
1–3
Baseline Order
Temperature
Compensation
On, Off
Off
tempcomp
Salinity Fitting
On, Off
On
salinfit
Bromide Tracing
On, Off
Off
brmtrace
Absorbance Cutoff
0.01–10.0
1.3
a_cutoff
Integration Time
Adjustment
Off, On, Persistent
On
intpradj
Integration Time Factor
1–20
1
intprfac
Integration Time Step
1–20
20
intadstp
Integration Time Max
1–20
20
intadmax
The processing configuration parameters completely determine how the spectrum is
processed. Some of the parameters are applicable only in some cases; non-applicable
(N/A) parameters are ignored. TS correction processing, even if configured, will only
proceed if temperature and salinity values have been provided via the APF CTD
command. The following table gives the valid parameter combinations.
Table 15: Combinations of data processing configuration parameters
Processing Mode
Fit
Br
TS
Con. Trace Cmp.
Sal.
Fit.
Comment
Freshwater
1
Off
N/A
N/A
Freshwater
and bromide trace
1
On
N/A
N/A
Fit 3 species
3
N/A
Off
N/A
Non-T-S correcting processing
T correction (fit S)
3
N/A
On
On
If T unavailable, uses Fit 3 species
TS correction
3
N/A
On
Off
If TS unavailable, uses Fit 3 species
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4. Terminal Interface of the SUNA
4.2.4 Polled Mode Commands
Polled mode is useful when the sensor is externally controlled. The sensor waits in low
power standby for activity on its input line, and after initialization confirms its readiness
to respond to commands via the CMD? prompt. The polled mode timeout setting
controls for how long the sensor stays at the polled mode prompt before returning to low
power standby.
Polled mode commands are:
Start
begin continuous data acquisition, terminate by sending the $ character
Measure N
take N light data frames (if N is zero, take a single dark data frame)
Timed N
take light data frames for a duration of N seconds
CTD
send CTD data for temperature-salinity correction
(sensor must be able to perform temperature-salinity correction,
and processing must be configured for it)
Status
print a sensor status message
SATMSG,SUNA,S/N,LampTime,Humidity,Voltage,LampTemp,SpecTemp
$
enter command line
Sleep
enter low power standby
4.2.5 SDI-12 Mode Commands
The SUNA supports all basic SDI-12 commands, as required by Version 1.3 of the SDI12 Specification. The commands and the SUNA response are described below. In these
descriptions, 'a' refers to the SUNA's SDI-12 address, <CRC> refers to the 3-character
Cyclic Redundancy Check Sum, <CR> indicates a carriage return character, and <LF>
indicates a line feed character. The SUNA's address defaults to 0 but is configurable by
the user. For commands not supported or explicitly described below, the SUNA
responds per the SDI-12 v1.3 specification. Details of the command protocol are beyond
the scope of this document. Interested users should refer to the SDI-12 specification.
SDI-12 operation has been tested using the SDI-12 Verifier from NR Systems Inc
(http://www.sdi-12-verifier.com).
In SDI-12 operation, internal data logging can be used to collect full spectral data. Data
can then be retrieved after deployment for further analysis or data reprocessing. If a
wiper is integrated, SDI-12 measurement commands will cause the wiper to sweep
before each measurement, adding to the time it takes to perform a measurement.
Command:
Acknowledge Active (a!)
Response:
a<CR><LF>
Notes:
confirms SUNA SDI-12 address
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4. Terminal Interface of the SUNA
Command:
Send Identification (aI!)
Response:
allccccccccmmmmmmvvvxxxxxxxxxxxxx<CR><LF>
Notes:
a
SUNA address
ll
2 character SDI-12 version, e.g. 13 for version 1.3
cccccccc
8 character Vendor identification, in this case SATLANTC
mmmmmm
6 character sensor model, in this case SUNA
vvv
3 character sensor version, e.g. v2
xxxxxxxxxxxxx
up to 13 character optional field, here used for firmware version.
Format: F<MAJOR>.<MINOR>.<PATCH>
If the SUNA determines that the firmware information will not fit in the
allocated space, it will not output this field.
An example response is 013SATLANTC SUNA v2 0002F2.1.2<CR><LF>
Command:
Change Address (aAb!)
Response:
b<CR><LF>
Notes:
SUNA responds with its new SDI-12 address: b
Command:
Address Query (?!)
Response:
a<CR><LF>
Notes:
SUNA responds with its SDI-12 address: a
Command:
Verify (V!)
Response:
atttn<CR><LF>
Notes:
SUNA always responds with a0000<CR><LF>
No SDI-12 diagnostic information is supported.
Command:
Measurement (aM!)
Measurement and CRC (aMC!)
Concurrent Measurements (aC!)
Concurrent Measurements and CRC (aCC!)
Response:
atttn<CR><LF>
atttnn<CR><LF>
(measurement)
(concurrent measurement)
Notes:
ttt
the time, in seconds, until the sensor will have a measurement ready. The
SUNA normally responds within less than 30 seconds.
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4. Terminal Interface of the SUNA
n or nn
the number of measurement values the SUNA will return in one or more
subsequent send data commands. For the SUNA, this value is 4.
For example: 00104<CR><LF>
001004<CR><LF>
(measurement)
(concurrent measurement)
The SUNA reports 10 seconds are required to make the measurements. Generally it will
complete sooner and issue a service request to the controller.
In subsequent data commands, the four values returned will be:
nitrate concentration [µM]
nitrogen in nitrate concentration [mg/l]
light spectrum average
dark spectrum average
Commands: Additional
Additional
Additional
Additional
Response:
Measurements (aM1!)
Measurements and CRC (aMC1!)
Concurrent Measurements (aC1!)
Concurrent Measurements and CRC (aCC1!)
atttn<CR><LF>
atttnn<CR><LF>
(measurement)
(concurrent measurement)
Notes:
ttt
the time, in seconds, until the sensor will have a measurement ready.
The SUNA normally responds with 4 seconds
n or nn
the number of measurement values the SUNA will return in one or more
subsequent send data commands. For the SUNA, this value is 7.
For example: 00047<CR><LF>
000407<CR><LF>
(measurement)
(concurrent measurement)
In subsequent data commands, the seven values returned will be:
lamp temperature [C]
spectrometer temperature [C]
lamp time [s]
relative humidity [%]
internal voltage [V]
regulated voltage [V]
supply voltage [V]
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4. Terminal Interface of the SUNA
Commands: Additional
Additional
Additional
Additional
Response:
Measurements (aM2!),
Measurements and CRC (aMC2!),
Concurrent Measurements (aC2!),
Concurrent Measurements and CRC (aCC2!),
atttn<CR><LF>
atttnn<CR><LF>
(measurement)
(concurrent measurement)
Notes:
ttt
the time, in seconds, until the sensor will have a measurement ready.
The SUNA normally responds with 4 seconds
n or nn
the number of measurement values the SUNA will return in one or more
subsequent send data commands. For the SUNA, this value is 7.
For example: 00109<CR><LF>
001013<CR><LF>
(measurement)
(concurrent measurement)
In subsequent data commands, the 9 (or 13 for concurrent measurements) values
returned will be:
nitrate concentration [µM]
nitrogen in nitrate concentration [mg/l]
light spectrum average
dark spectrum average
measurement date
measurement time
absorbance at 254 nm
absorbance at 350 nm
bromide trace
lamp temperature [C]
(concurrent
spectrometer temp. [C]
(concurrent
relative humidity [%]
(concurrent
rmse of nitrate processing (concurrent
measurement only)
measurement only)
measurement only)
measurement only)
Command:
Additional
Additional
Additional
Additional
Measurements (aM3! - aM9!),
Measurements and CRC (aMC3! - aMC9!),
Concurrent Measurements (aC3! - aC9!),
Concurrent Measurements and CRC (aCC3! - aCC9!)
Response:
atttn<CR><LF>
atttnn<CR><LF>
Notes:
The SUNA supports only 2 additional measurements.
ttt is always 000.
n is always 0.
nn is always 00.
(measurement)
(concurrent measurement)
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4. Terminal Interface of the SUNA
Command:
Send Data (aD0! - aD9!)
Response:
or
a<values><CR><LF>
a<values><CRC><CR><LF>
Notes:
Sends group of data to the controller after a measurement or verification
command. The response will vary depending on the previous
measurement command.
After the M! or C! command, the SUNA will respond with the 4 above listed values
(nitrate concentration in two units, light and dark spectrum average).
For example: 0+1039.040+14.8434+22799+671<CR><LF>
After the MC! or CC! command, the SUNA will respond as per the M! or C! command,
but with a CRC value attached.
For example: 0+1038.452+14.8350+22683+672NtW<CR><LF>
After the M1! command, the SUNA will respond to the aD0! command with the first 4
values that are listed above (two temperatures, lamp time and humidity).
For example: 0+33.188+23.500+3315+23.2<CR><LF>
The SUNA will then respond to the aD1! Command with the remaining 3 values (three
voltages).
For example: 0+11.92+5.43+13.68<CR><LF>
After the MC1! command, the SUNA will respond as per the M1! command, but with a
CRC value attached.
For example: 0+33.813+23.500+3356+23.2AsF<CR><LF>,
followed by 0+11.92+5.43+13.62EyF<CR><LF>
The response to the aC1!, aCC1!, aM2!, aMC2!, aC2!, aCC2! commands follows an
analogous pattern.
Command:
Continuous Measurements (aR0! - aR9!),
Continuous Measurements and Request CRC (aRC0! - aRC9!)
Response:
a<values><CR><LF>
Notes:
Continuous measurements are not supported by the SUNA in SDI-12
mode due to limited lamp life time. The SUNA will always report
a0<CR><LF> or a0<CRC><CR><LF>.
4.2.6 Analog Output
The SUNA can work with analog input data acquisition systems, such as a Sea-Bird
CTD profiler, by using the optional analog output system. The analog interface allows
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4. Terminal Interface of the SUNA
merging of nitrate data with other data recorded at the same time. A standard
application is to integrate the voltage signal into a CTD profiler's auxiliary port, providing
a profile of conductivity, temperature, and nitrate versus depth.
Generating Voltage and Current for a Nitrate Concentration
The SUNA generates analog voltage and current representations of the calculated
nitrate values. The voltage is generated using a precision 12-bit digital-to-analog
converter (DAC) and is in the range of 0.095 to 4.095 Volts. The current is generated
using a precision 16-bit DAC and is in the range of 4 to 20 mA.
The SUNA has two configuration values, DAC Minimum Nitrate and DAC Maximum
Nitrate, that correspond to the lower and upper bounds of the voltage and current
output. If the nitrate concentration is below the DAC Minimum, the output voltage and
current will be the minimum voltage or current. If the nitrate concentration is above the
DAC Maximum, the output voltage and current will be the maximum voltage or current.
Otherwise, the voltage and current are calculated via
V max −V min
⋅(C
−DAC min ) and
DAC max −DAC min nitrate
I max−I min
I =I min +
⋅(C
−DAC min ) ,
DAC max−DAC min nitrate
V =V min+
where
C nitrate
is the nitrate concentrations
DAC min
is the nitrate concentration at minimum voltage and current
DAC max
is the nitrate concentration at maximum voltage and current
V
is the generated voltage
V min
is 0.095 V, the minimum voltage
V max
is 4.095 V, the maximum voltage
I
is the generated current
I min
is 4 mA, the minimum current
I max
is 20 mA, the maximum current
The actual voltage or current may differ slightly from the theoretical values. See below
on how to accurately calibrate the analog output system.
Calculating Nitrate Concentration from Voltage and Current
The inverse voltage and current equations are
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4. Terminal Interface of the SUNA
DAC max−DAC min
⋅(V −V min ) and
V max−V min
DAC max−DAC min
C nitrate=DAC min +
⋅( I− I min ) ,
I max−I min
C nitrate=DAC min +
using the same symbols as above.
These equation can be written more compact as
C nitrate= A0+A1⋅V and
C nitrate=B0+B 1⋅I ,
where
DAC max −DAC min
V max −V min
is the voltage scale coefficient
A0 =DAC min− A1⋅V min
is the voltage offset coefficient
DAC max−DAC min
I max− I min
is the current scale coefficient
A1=
B1=
B0=DAC min−B1⋅I min
is the current offset coefficient
In-System Calibration
The above defined scale and offset coefficients are based on the nominal minimum and
maximum voltage and current values. In a deployed system, voltage and current may
differ, due to transmission losses. Ideally, the true low and high voltage or current values
are used instead of the nominal values.
In order to perform an in-system calibration, a Y-cable is required, that connects the
SUNA to both the data acquisition device and a computer. Please contact Satlantic for
assistance in creating or purchasing such a cable. With this cable in place, the SUNA is
tasked to generate the low DAC and then the high DAC output. The low and high
voltage or current values are measured in the data acquisition device, and used to
calculate the in-system scale and offset coefficients:
A1=
DAC max −DAC min
V high−V low
A0 =DAC min− A1⋅V low
B1 =
DAC max−DAC min
I high−I low
is the in-system calibrated voltage scale coefficient
is the in-system calibrated voltage offset coefficient
is the in-system calibrated current scale coefficient
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4. Terminal Interface of the SUNA
B0=DAC min−B1⋅I low
is the in-system calibrated current offset coefficient
The SUNA can be tasked to generate the low and high analog output via SUNACom
(see the SUNACom user manual) or using the DAC Low and DAC High commands in
the terminal interface (see section 4.2.1 Status and Maintenance Commands).
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5. Configuration Parameters in Context
5. Configuration Parameters in Context
While section 4.2.3 Configuration Commands gives a complete list configuration
parameters, this section describes groups of configuration parameters that are related
because they are used alongside each other.
Configuration parameters are discussed in four categories: Build, Input/Output, Data
Acquisition, Data Processing.
5.1 Build Configuration
Build configuration parameters describe the hardware of the sensor, and determine
which capabilities are available. Build parameters limit the values some other
configuration parameters can take. Only some combinations of build parameters are
supported.
Sensor Identification:
Sensor Type
Sensor Version
Sensor Serial Number
SUNA
V2
0000–9999
Table 16: SUNA build variants
Option
Description
Super capacitors Provides short-term power in case when power is lost
PCB supervisor
Provides low-power sleep state
Relay
Allows the SUNA to disconnect itself from its power supply
Analog output
Generates a voltage or current representation of the nitrate values
SDI-12
Allows the SUNA to operate as a SDI-12 client
USB
Allows interfacing via USB, higher data rates than via serial
communication
Internal logging
Permits the SUNA to operate as its own data logger
Scheduling
Permits the SUNA to autonomously schedule its data acquisition
APF Mode &
T-S Correction
Provides the interface protocol used in APEX floats, and supports
on-board temperature-salinity correction of nitrate values
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5. Configuration Parameters in Context
5.2 Input / Output Configuration
Input to the SUNA is via serial RS-232 or if available, via USB, or in SDI-12 mode, via
the SDI-12 port.
Output of the sensor is sent via serial RS-232. If available and connected, output is sent
via UBS. Data can also be logged internally to file, or converted to an analog voltage or
current for output.
With the exception of SDI-12 mode, output generation is independent of the operation
mode (see next section), and multiple output destinations can be served concurrently.
Baud Rate
Message Level
Message File Size
The RS-232 data rate.
Error, Warning, Info, Debug, Trace
0–65 [MB]
The sensor generates log messages. The selected message level determines the
amount of logging: the least messages are generated for the Error message level, and
the most are generated for the Trace message level. Messages are always sent to RS232, and logged internally if the sensor is equipped with internal logging. Internal
logging of messages can be switched off by setting the message file size to zero.
Output Frame Type
Logging Frame Type
Output Dark Frames
Logging Dark Frames
Logging File Type
Data File Size
Full_ASCII, Full_Binary, Reduced_Binary,
Concentration, APF, MBARI, None
Full_ASCII, Full_Binary, Reduced_Binary,
Concentration, APF, MBARI, None
Suppress, Output
Suppress, Output
Acquisition, Continuous, Daily
1–99 [MB]
Digital output of data is in the form of fixed or variable length strings of bytes (see
section 7. SUNA Frame Definitions). If output or internal logging of frames is not
desired, the frame type is set to None. Omitting frame generation, output, and logging
when not needed increases the data rate of the sensor.
Dark data frames may be useful for monitoring sensor performance, but are not needed
for regular data acquisition. When acquisition time and/or transfer speed or volume are
an issue, dark frame output and logging can be suppressed.
Internal data log files are generated with an automated naming schema. Files may be
per Acquisition (a new file with each power-up), or Daily (all data collected at one day
are placed into a single file), or Continuous (a new file is started when the current file
reaches a configured size).
The data log file type should be chosen to match the planned data acquisition and the
intended method of data utilization.
For moored deployments, either in periodic mode or scheduled by a controller, daily
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5. Configuration Parameters in Context
data log files are a good choice: The number of files generated over a number of
months is modest, while it is easy to select data for a range of dates. If per-acquisition
data log files were used instead, many thousand files could be generated. While a
SUNA can manage such a number of files, it may become slower. Generally, managing
thousands of files can be cumbersome.
For profiles, which are typically collected in continuous operation, per acquisition data
log files are a convenient choice: All data between power up and power down will be
placed into the same file, facilitating subsequent data management. Using daily or
continuous data log files when acquiring multiple profiles can split a profile into two files,
requiring manual realignment.
Continuous data log files in conjunction with the maximum data log file size offer control
over the number of files and the size of the files that will be generated.
When logging data on board the SUNA, care should be taken to ensure there is
sufficient space on the file system. Ideally, data are off-loaded from the SUNA prior to
deployment, and the file system cleared as much as possible. When the on board file
system is full, subsequent data can no longer be logged and will be lost.
DAC Minimum
DAC Maximum
Nitrate concentration representing minimum analog output.
Nitrate concentration representing maximum analog output.
SDI-12 Address
The address used by the sensor in SDI-12 mode. It is a number
from 48 to 57, corresponding to ASCII values '0' to '9'.
5.3 Data Acquisition Configuration
Data acquisition is primarily controlled via the operating mode. Each operating mode
has secondary configuration parameters for fine tuning. Both data processing and
output generation configuration are independent of the data acquisition scheme. The
exception is SDI-12 mode, which has its own output interface.
In the following paragraphs, each operating mode is described, and the configuration
parameters relevant to that operating mode are explained.
5.3.1 Continuous and Fixed-time Operating Mode
Continuous mode generates an uninterrupted stream of data. Data collection is
autonomous.
When powered, the sensor starts collecting and outputting data. Data acquisition ends
when power is removed or the $ character is sent via serial input. In fixed time mode,
data acquisition proceeds for the maximum time configured via fixed-time duration, after
which the sensor enters low-power standby.
When collecting data in continuous mode, changes in the spectrometer temperature
impact the measured concentrations. For best accuracy, regular dark measurements
are required to compensate for the changing temperature. The user can choose a dark
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5. Configuration Parameters in Context
to light data rate based either of a number of samples or on the duration, via the
Operation Control configuration parameter. Then, the sensor will collect data in a DL-...-L-D-...-D-L... schema. If operation control is SAMPLES based, the user controls the
respective numbers via the Light Samples and Dark Samples configuration parameters.
When operation control is DURATION based, the user controls the respective durations
via the Light Duration and Dark Duration configuration parameters.
Configuration: Operation Control, Countdown, Light Samples, Dark Samples, Light
Duration, Dark Duration.
5.3.2 Periodic Operating Mode
Periodic mode generates short bursts of data at pre-configured times. Data collection is
autonomous.
When powered, the sensor enters low-power standby. Any activity on RS-232 or USB
brings the sensor within three seconds to the command interface, indicated by SUNA>.
After a duration of Countdown seconds (configuration parameter) without input, the
sensor returns to low power standby.
At the pre-configured times, the sensor collects a fixed number of data points, or data
points for a fixed duration. After data collection, the sensor returns to low-power
standby.
The start times of the data collection events are separated by a fixed interval. Possible
values for the interval are 1, 2, 5, 10, 12, 15, 30, minutes, or 1, 2, 3, 4, 6, 12, or 24
hours. The time grid starts relative to the start of the day. The time grid can be offset
from the start of the day via the Periodic Offset configuration parameter.
The data collection event can be either sample or duration based. This is controlled via
the Operation Control configuration parameter. For sample based data collection, the
Periodic Duration configuration parameter determines the number of data samples that
will be collected. For duration based data collection, the Periodic Duration configuration
parameter determines the number of seconds over which data will be collected.
Configuration: Operation Control, Periodic Interval, Periodic Offset, Periodic Duration,
Periodic Samples, Countdown
5.3.3 Polled Operating Mode
Polled mode generates data in response to a command. Data collection is driven by a
controller via the serial interface.
When powered, the sensor enters a low power standby. Any activity on RS-232 or USB
brings the sensor within three seconds to the polled command prompt, indicated by
CMD?. After a duration of Polled Timeout (configuration parameter, in seconds) without
command input, the sensor returns to low power standby.
Supported commands are described in section 4.2.4 Polled Mode Commands.
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5. Configuration Parameters in Context
Configuration: Polled timeout, Skip Sleep
5.3.4 SDI-12 Operating Mode
SDI-12 mode generates data in response to a command. Data collection is SDI-12
controller driven. When powered, the sensor enters a standby state where it responds
only to SDI-12 commands. The sensor interface conforms to the SDI-12 protocol.
Sending a $ character via the RS-232 port gives access to the command prompt.
Supported commands are described in section 4.2.5 SDI-12 Mode Commands.
Configuration: SDI-12 Address
Table 17: Data acquisition configuration parameters by operating mode.
Name
Acceptable Values
Operation mode
Continuous, Fixedtime, Periodic,
Polled, SDI12
Operation control
Samples, Duration
Explaining Subsection
Continuous mode,
Periodic mode
Fixed time duration 1–1000000
Continuous mode
Light samples
1–65535
Continuous mode
Dark samples
1–65535
Continuous mode
Light duration
1–65535
Continuous mode
Dark duration
1–65535
Continuous mode
Periodic interval
1m, 2m, 5m, 6m, 10m, 15m, 20m, 30m, Periodic mode
1h, 2h, 3h, 4h, 6h, 8h, 12h, 24h
Periodic offset
0–86399
Periodic mode
Periodic samples
1–255
Periodic mode
Periodic duration
1–255
Periodic mode
Polled timeout
0–65535
Polled mode
APF timeout
1–100
APF mode
Skip Sleep at Start
On, Off
Polled mode,
APF mode
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5. Configuration Parameters in Context
5.4 Data Processing Configuration
Data processing is independent of input/output and data acquisition configuration.
5.4.1 Basic Data Processing
Data processing normally uses the 217 to 240 nm interval of the measured spectrum.
The measured absorbance in that interval is decomposed into absorbances due to
individual absorbers, and the absorbance due to an absorber is converted to a
concentration value for that absorber.
The sensor can decompose the absorbance either solely into nitrate (freshwater use) or,
if calibrated for this, into nitrate, seawater, and seawater temperature effects
(oceanographic use). If a sensor has been calibrated for oceanographic use, but is to be
used in a freshwater environment where the salinity will be below 1 PSU, the user
should constrain data processing to use only nitrate decomposition by setting the
Concentrations-to-Fit configuration parameter from 3 to 1. Reducing the number of
concentrations to fit improves the precision of the processed data.
Under normal conditions, no other processing parameters need to be changed.
Configuration: Concentrations to Fit, Fit Wavelength Low, Fit Wavelength High
5.4.2 Special Case: Bromide Tracing
In freshwater, bromide can be used as a tracer. If the sensor's Bromide Trace
configuration parameter is set to On, the sensor will analyze the measured spectrum for
the presence of bromide, and output the result in its regular frame.
Configuration: Bromide Tracing
5.4.3 Special Case: Highly Absorbing Water
Highly absorbing waters pose a challenge to the sensor. In its normal configuration, the
part of the spectrum with an absorbance of more than 1.3 is excluded from processing.
Using parts of the spectrum of higher absorbance will reduce accuracy and precision of
the measured concentrations. The user may increase the Absorbance Cutoff to a higher
value, to extend the operational range of the sensor at the expense of reduced data
quality.
If the absorbance reaches values between 2.0 and 2.5, data quality deteriorates further.
If the Integration Time Adjustment configuration parameter is set to On or Persistent,
the sensor will start making measurement using a spectrometer integration time that is
20 times as long as the normal integration time. This longer integration time increases
the signal-to-noise ratio in faint light conditions, and allows the sensor to operate in
optically dense conditions. When the optical density drops, the sensor will revert to the
normal spectrometer integration time.
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5. Configuration Parameters in Context
Configuration: Absorbance Cutoff, Integration Time Adjustment, Integration Time
Factor, Integration Time Step, Integration Time Maximum Factor.
Table 18: Data processing configuration parameters in use case context
Name
Acceptable Values
Subsection for Explanation
Lower limit of fit interval
217–350
Basic processing
Upper limit of fit interval
217–350
Basic processing
Concentrations to fit
1–3
Basic processing
Temperature correction
On, Off
Temperature-Salinity Correction
Salinity fitting
On, Off
Temperature-Salinity Correction
Bromide tracing
On, Off
Bromide Tracing
Absorbance cutoff
0.01–10.0
Highly Absorbing Water
Integration Time Adjustment
Off, On, Persistent
Highly Absorbing Water
Integration Time Factor
1–20
Highly Absorbing Water
Integration Time Step
1–20
Highly Absorbing Water
Integration Time Maximum
1–20
Highly Absorbing Water
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6. Use Scenarios
6. Use Scenarios
6.1 Profiling
6.1.1 Objectives and Considerations
A profile is a continuous series of measurements taken over a depth range, where
nitrate concentrations may be collected for either down and up cast or both. The
descent and ascent rate together with the sensor's data rate determine the spatial
resolution of the profile.
The data rate depends on a number of factors. The integration period of the
spectrometer sets a lower limit on the data rate. Additional time is required for data
processing and data output. Output, even at high baud rates, is always slower than
internal logging of data.
6.1.2 Example
This example assumes that the sensor is not outputting any data, but only logging data
internally. The ascend and/or descend rates of the profiler are assumed to be rather
modest, thus internal averaging of spectra is used to obtain improved data quality.
It is further assumed that temperature and salinity data are collected alongside the
sensor, for post-processing employing temperature-salinity correction. Therefore, full
spectral data are logged.
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6. Use Scenarios
Setting Parameter
Input /
Output
Data
Acquisition
Process
Value in Profiling Deployment
Message Level
Warn
Message File Size
2
Output Frame
None.
Logging Frame
Full_ASCII
Logging Dark Frame
Output
Log File Type
Acquisition
Operation Mode
Continuous
Operation Control
Samples
External Device
None
Countdown
15
Dark Averages
1
Light Averages
5
Dark Samples
1
Light Samples
60
Temperature Compensation
Off
Salinity Fitting
On
Bromide Tracing
Off
Concentrations to fit
3
Dark Correction Method
SpecAverage
Absorbance Cutoff
1.3
Integration Time Adjustment
On
Fit Wavelength Low / High
217, 240
Table 19: Configuration parameters illustrating a profiling deployment.
6.2 Moored
6.2.1 Objectives and Considerations
In moored applications, power management, especially if running from battery, has to be
considered.
Moored applications typically have infrequent service intervals. As most environments
cause bio-fouling of the sensor, either passive (fouling guard) or active (wiper) counterCopyright © 2013, Satlantic LP, All rights reserved
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6. Use Scenarios
measures are necessary.
The sensor can run autonomously (periodic mode), respond to a controller (polled, APF,
or SDI-12 mode), or be powered up and down by a controller (running in continuous
mode).
Regardless of the operation control, moored applications often collect discrete samples.
The user can choose to either collect a series of samples, and perform averaging as a
second data processing step. Alternatively, the sensor can be configured to collect a
single data sample that already is an average of multiple measurements.
Before the deployment, the sensor must receive a reference spectrum update, where
the reference spectrum is collected under data acquisition conditions that resemble the
deployment data collection conditions.
6.2.2 Example
This example assumes that the SUNA operates autonomously in periodic operating
mode. Data are collected in analog form by a data acquisition device, and also logged
internally for post-deployment analysis.
The SUNA is also equipped with a wiper, that is internally controlled. It takes the wiper
some 15 seconds to complete a sweep through the sampling volume. The wiper speed
is highest for an unobstructed sampling volume, and when operating at the upper input
voltage range. The minimum required delay between subsequent wipes is 30 seconds.
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6. Use Scenarios
Setting Parameter
Input /
Output
Data
Acquisition
Process
Value in Moored Deployment
Message Level
Info
Message File Size
2
Output Frame
None.
Logging Frame
Full_ASCII or Full_Binary
Logging Dark Frame
Output
Log File Type
Acquisition
Operation Mode
Periodic
Operation Control
Samples
External Device
Wiper
External Pre-Run Time
15
Periodic Interval
15m
Periodic Samples
10
Dark Averages
1
Light Averages
1
Temperature Compensation
Off
Salinity Fitting
On
Bromide Tracing
Off
Concentrations to fit
3
Dark Correction Method
SpecAverage
Absorbance Cutoff
1.3
Integration Time Adjustment
On
Fit Wavelength Low / High
217, 240
Table 20: Configuration parameters illustrating a moored deployment.
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7. SUNA Frame Definitions
7. SUNA Frame Definitions
7.1 Frames with Synchronization Headers
The frames described in this section start with a ten character header which uniquely
identifies the sensor and data type. The unique header allows to extract sensor specific
frames from arbitrary collections of data.
There are two types of such frames: Variable length frames and fixed length frames. In
variable length frames, the fields are in ASCII format and comma separated . In fixed
length frames, each field has a fixed size, and is usually in binary format.
The variable length frame headers start with SAT, followed by three characters
identifying the frame type. SATSLF and SATSDF for full ASCII light and dark frames,
and SATSLC and SATSDC for concentration light and dark frames, respectively. The
last four characters are the sensor serial number. Example for serial number 1234:
SATSLC1234 for concentration light frame.
The fixed length frame headers start with SAT, followed by three characters identifying
the frame type: SATSLB and SATSDB for full binary light and dark frames, and SATSLR
and SATSDR for reduced binary and dark frames, respectively. The last four characters
are the sensor serial number. Example for serial number 1234: SATSLR1234 for
reduced binary light frame.
For each field in these frames, format and size are given. The formats are ASCII Integer
(AI), ASCII Float (AF), ASCII String (AS), Binary Unsigned Integer (BU), Binary Float
(BF), and Binary Double (BD). Binary fields have fixed sizes, ASCII fields may have
fixed or variable sizes. BF and BD data formats conform to the IEEE 754 standard.
Binary data are in big endian order.
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7. SUNA Frame Definitions
Table 21: Synchronization header frame definitions
Field
Header and Serial Number
Concentration
SATSLCnnnn
SATSDCnnnn
Full ASCII
SATSLFnnnn
SATSDFnnnn
Full Binary
SATSLBnnnn
SATSDBnnnn
Reduced Binary
SATSLRnnnn
SATSDRnnnn
Date, year and day-of-year
AI 7
AI 7
BS 4
BS 4
Time, hours of day
AF
AF
BD 8
BD 8
Nitrate concentration [μM]
AF
AF
BF 4
BF 4
Nitrogen in nitrate [mg/l]
AF
AF
BF 4
BF 4
Absorbance at 254 nm
AF
AF
BF 4
BF 4
Absorbance at 350 nm
AF
AF
BF 4
BF 4
Bromide trace [mg/l]
AF
AF
BF 4
BF 4
Spectrum average
−
AI
BU 2
BU 2
Dark value used for fit
−
AI
BU 2
BU 2
Integration time factor
−
AI
BU 1
BU 1
Spectrum channels
−
256 x AI
256 x BU 2
32 x BU 2
Internal temperature [˚C]
−
AF
BF 4
−
Spectrometer temperature [˚C]
−
AF
BF 4
BF 4
Lamp temperature [˚C]
−
AF
BF 4
BF 4
Cumulative lamp on-time [s]
−
AI
BU 4
−
Relative Humidity [%]
−
AF
BF 4
BF 4
Main Voltage [V]
−
AF
BF 4
−
Lamp Voltage [V]
−
AF
BF 4
−
Internal Voltage [V]
−
AF
BF 4
−
Main Current [mA]
−
AF
BF 4
−
Fit Aux 1
−
AF
BF 4
−
Fit Aux 2
−
AF
BF 4
−
Fit Base 1
−
AF
BF 4
−
Fit Base 2
−
AF
BF 4
−
Fit RMSE
AF
AF
BF 4
BF 4
CTD Time [seconds since 1970]
−
AI
BU 4
BU 4
CTD Salinity [PSU]
−
AF
BF 4
BF 4
CTD Temperature [˚C]
−
AF
BF 4
BF 4
CTD Pressure [dBar]
−
AF
BF 4
BF 4
Check Sum
−
AI
BU 1
BU 1
Terminator
CR LF
CR LF
−
−
7.2 APF Frame
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7. SUNA Frame Definitions
Fields in the APF frame are comma separated.
Table 22: APF data frame definition
Frame Field
Example Value
Record 16-bit CRC
0xE0B6
Record Data Type
A
Timestamp (GMT)
7/22/2011 19:04
CTD Timestamp (1970 epoch seconds)
0
CTD Pressure (dBar)
-1
CTD Temperature [˚C]
-1
CTD Salinity
-1
Sample Counter
246
Power Cycle Counter
3
Error Counter
1
Internal Temperature [˚C]
27.34
Spectrometer Temperature [˚C]
28.12
Internal Relative Humidity (%)
4.21
Supply Voltage (V)
11.78
Supply Current (A)
0.523
Reference Detector Mean
2345
Reference Detector Standard Deviation
6.54
Dark Spectrum Mean
567
Dark Spectrum Standard Deviation
7.23
Sensor Salinity
32.23
Sensor Nitrate
12.21
Absorbance Fit Residuals (RMS)
1.23E-04
Output Pixel Begin
33
Output Pixel End
63
Output Spectrum (Hex Packed, 4 characters for
each output channel, Begin-End+1 channels
0701079D085B092009F90ADC0BDD0CFC0E370F
88110512A41470165D187A1AAA1...
Seawater Dark (Mean of Channels 1 to 5)
591.2
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7. SUNA Frame Definitions
7.3 MBARI Frame
MBARI frames are generated for dark and for light spectrum measurements. Dark
frames begin with a D, light frames begin with an S. All fields in the MBARI frame are
comma separated.
Table 23: MBARI data frame definition
Frame Field
Example Value
Frame Type for dark frame, or
for light (spectrum) frame
D
S
Timestamp (GMT)
7/22/2011 19:04:23.1234
Internal Temperature [˚C]
27.34
Spectrum Average for dark frame, or
Reference Detector Average for light frame
2345.23
Spectrum Standard Deviation for dark frame, or 6.54
Reference Detector Std. Dev. for light frame
Output Spectrum (256 channels)
12345
Terminator
CR LF
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8. SUNA Calibration File
8. SUNA Calibration File
8.1 File Name
SUNA calibration files use the following file naming convention: The file name has a
base of eight letters and a three letter 'CAL' extension. The file name is not case
sensitive. The first three letters are 'SNA', followed by the four digits of the sensor serial
number, and the last letter is a version letter. Version letters run from A to Z.
8.2 File Format
SUNA calibration files are text files, consisting of a series of header lines followed by a
series of coefficient lines. A line is terminated by either a line feed character
(hexadecimal 0A) or by a carriage return character followed by a line feed character
(hexadecimal 0D 0A).
A header line always begins with the 'H,' character sequence, followed by auxiliary
information. A coefficient line always begins with the 'E,' character sequence, followed
by a series of comma separated floating point numbers.
The last line may be succeeded by a series of CTRL-Z (hexadecimal 1A) padding
characters. These are introduced by the XMODEM protocol that is used to transfer
calibration files from and to the SUNA, and must be ignored.
8.3 File Interpretation
The first header line always contains the sensor type (SUNA) and the sensor four digit
serial number, followed by some generic comments. Subsequent header lines contain
information about the generation.
If there is a header line with the keyword T_S_CORRECTABLE, the coefficients can be
used for temperature salinity correction.
The temperature of the calibration is given in the T_CAL header line. This temperature
is needed when applying the temperature salinity correction.
The last header line always consists of a comma separated list of labels. These labels
describe the content of the coefficient lines. The number of labels in this line must match
the number of entries in the coefficient lines. The first label is always Wavelength, the
second label is normally NO3, and the last label is always Reference. For sensors
calibrated for sea water, there are a SWA and a TSWA label between the NO3 and the
Reference label.
Calibration files are used by the SUNA for on-board processing and by SUNACom for
data re-processing.
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9. Firmware Upgrade
9. Firmware Upgrade
9.1 Firmware Upgrade Using SUNACom
The firmware upgrade can be initiated via the SUNACom. See section Upload Firmware
of the SUNACom user manual for details.
9.2 Firmware Upgrade Using the Terminal Interface
The firmware upgrade is initiated via the upgrade command given at the command line.
See section 4.2 Command Line Interface for details.
After the upgrade command, the SUNA's bootloader program executs. It reports to the
command line using the SATBLDR> prompt.
Use the w command to initiate the firmware upload. Then, send the firmware file using
the XMODEM protocol to the SUNA. Firmware files have the sfw file extension.
The bootloader rejects invalid or corrupt files. The user can check if the uploaded file is
valid by issuing the v (verify) command.
After a valid firmware file has been uploaded, use the a command to let the bootloader
execute the new firmware at power-up.
Then, power cycle the sensor. The new firmware will execute on the sensor.
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10. Troubleshooting
10. Troubleshooting
10.1 Sensor Is Not Responsive
Check Power
Confirm that sufficient power reaches the sensor. Use a voltage meter to confirm that
the power cable supplies 8–18 VDC (8–15 VDC for SUNA with an integrated wiper). See
section 3.2 Specifications for the cable pin-out.
Reset Sensor
It is possible for the sensor to get stuck in an undefined state if its input power is
sporadically out-of-range. In that case, the sensor should be powered down for 60
seconds, and then re-powered.
Check Power Consumption
Using a power supply with an accurate current indication will tell if the sensor is
operating at all, and what operating state it may be in.
If the current is above 500 mA, the sensor is acquiring data. Inserting a piece of white
paper into the sampling volume should show a bright spot, showing that the sensor lamp
is operating.
If the current is above 5 mA, the sensor is in standby, and should respond to input over
its serial input.
If the current is above 100 µA, the sensor is in a low-power mode, and should respond
to input over its serial input.
If the current is below 100 µA, the sensor is not operating. Please contact Satlantic for
further assistance.
Test Serial Cable
The sensor may appear to be non-responsive due to a faulty communication cable. The
user can check the communication cable for continuity. See section 3.2 Specifications
for the connector and cable pin-out.
Operating Mode
The sensor may be unresponsive to the received input because it is in an unexpected
operating mode. For example, if the sensor is in SDI-12 mode, it will not respond to
normal commands, or may not output data as in other operating modes.
If a connection via SUNACom does not succeed, a terminal emulator connection may
be attempted.
Regardless if the operating mode, sending a $ character to an operational sensor will
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10. Troubleshooting
generate a response.
If there is no response, please contact Satlantic for further assistance.
10.2 Sensor Output Is Unexpected
Unexpected results can take many forms. A sensor that performed fine over a long
period of time may suddenly report results that differ qualitatively or quantitatively from
previous results.
Below are listed a few checks that may identify the problem.
Warning or Error Messages
In case of obvious problems, the sensor outputs error or warning log messages. If the
sensor has internal logging capability, these are also logged to file. Monitoring the log
messages or reviewing the content of the message log file may point to the origin of the
problem.
Inaccurate Nitrate
Systematically inaccurate, but otherwise stable nitrate concentrations indicate the need
to clean the sensor windows and to perform a reference update.
A reference update is best performed from within the SUNACom software. A reference
update involves replacing the reference spectrum in the currently active calibration file
by a new reference spectrum. Detailed instructions are provided in the SUNACom user
manual.
If the concentrations inaccuracies persist, please contact Satlantic.
Imprecise or Noisy Nitrate, Low Spectral Intensity
If the nitrate concentration changes by more than 25 μM within a few samples while
measuring a stable water sample, the measured spectral intensity is usually too low.
The spectral intensity of the sensor drops when the optical path gets obstructed or if
optical component degrade.
Obstructions may be due to a change in the water content, or due to accumulation of
matter (bio film, settled particles) in the sampling volume. If the spectral intensity
remains low after cleaning of the sample volume, and especially the windows, please
contact Satlantic.
High Humidity
If the relative humidity inside the sensor exceeds 90%, the sensor may have developed
a leak, and needs to be returned to Satlantic for service. High humidity is problematic
because it leads to failure of sensor components. Furthermore, high humidity may lead
to condensation on optical components, making measurements inaccurate.
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11. Accessories
11. Accessories
11.1 Foul Guard
The foul guard is an optional accessory used for moored applications without an active
pumping system. The foul guard consists of a strip of perforated copper plate that is
formed around the SUNA sample volume. The guard is secured to the SUNA by a
plastic clamp. The copper inhibits biofouling while the perforations allow passive flushing
of the sample volume. When using the foul guard, the SUNA should be mounted so that
the optical chamber is mounted at 90 degrees to the vertical. This orientation helps to
prevent air bubbles and sediment from becoming trapped in the sample volume.
Illustration 6: Foul Guard
11.2 Wiper
The Zebra-Tech Hydro-Wiper is available as an integrated accessory. The wiper gently
brushes the sample chamber to remove biological growth and particulate deposits from
the optical path, ensuring consistent sampling conditions and data quality. The wiper
reduces the need for site visits to manually clean the instrument, maintaining data
quality through long deployments in harsh environments.
The integrated Hydro-Wiper is controlled by the SUNA and works with all operating
modes such as periodic and polled modes. The wiper performs a single sweep before
each sampling event. This option simplifies cabling and integration requirements for the
user. The integrated Hydro-Wiper is not available for the Deep SUNA.
The wiper sweep angle is 90° for new models, 150° for old builds. For proper operation,
the wiper movement must not be obstructed. The drawing below gives the minimum
space requirements.
The wiper drive shaft features a slip mechanism, so the wiper arm can be manually
moved if necessary. This also protects the wiper from damage if the wiper arm is
subject to force during operation.
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11. Accessories
Illustration 7: SUNA with integrated wiper.
Illustration 8: Space requirements for the integrated wiper.
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11. Accessories
11.3 Flow Cell
The flow cell is an optional accessory used for moored applications with a pumped
circulation system. It is also useful for calibration updates. The flow cell consists of a
plastic cell that seals against the instrument housing and directs pumped flow across the
optical path of the SUNA. The flow cell is equipped with a copper tube on the inlet port
and a plastic barbed fitting on the outlet port that would be connected to the pump by
flexible tubing. The kit includes additional elbow fittings that may be installed on the inlet
or outlet ports to suit the physical arrangement of the instrument for deployment. The
flow cell is secured to the SUNA by a plastic clamp. O-rings ensure the flow cell seals
tightly around the sample volume.
Illustration 9: Flow Cell
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12. Maintenance
12. Maintenance
Before a deployment, and regularly during the deployment, the sensor windows have to
be cleaned. At the same time, the reference spectrum should be updated.
A reference update is best performed from within the SUNACom software. A reference
update involves replacing the reference spectrum in the currently active cal file by a new
reference spectrum. Detailed instructions are provided in the SUNACom user manual.
After every deployment, the sensor must be cleaned with freshwater prior to storage.
Corrosion resulting from failure to do so is not covered under warranty.
At regular intervals, check the sensor's internal humidity. If the humidity increases by
more than a few percent per day, there is the possibility of a leak, and servicing is
suggested.
At regular intervals, check the spectral intensity in pure water. While the optical intensity
is expected to decrease over time, sudden changes in intensity may indicate problems
with a sensor subsystem. Contact Satlantic if there is a sudden drop in intensity by more
than 20%.
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13. Safety And Hazards
13. Safety And Hazards
13.1 Pressure Hazard
Warning! If you suspect that the sensor has flooded, use extreme caution around the
sensor. If the sensor leaked at depth it might remain pressurized when recovered. If you
suspect a flood, make sure to check the sensor for signs of pressurization. If the sensor
is pressurized you may notice the gap between the end cap and pressure case look to
be extended.
To relieve the sensor pressure, stand to the side of the sensor. Relieve the pressure by
very slowly unscrewing the bulkhead connector. Be extremely careful, as if the sensor is
pressurized the connector may be forced out of the housing with extreme force and at
high velocity.
13.2 Electrical Hazard
Use care when connecting power supply cables to the sensor. A shorted power supply
or battery can output maximum current, potentially harming the user or the equipment.
When transporting or shipping, install the dummy plug with locking sleeve on the sensor
connector to prevent accidental shorting of the terminals.
Handle electrical terminations carefully, as they are not designed to withstand strain.
Disconnect the cables from the bulkhead connector by pulling on the connector heads
and not on the cables. Do not twist or wiggle the connector while pulling, as this will
damage the connector pins.
Do not use petroleum-based lubricants on connectors. Connectors should be free of dirt
and lightly lubricated before mating. We recommend applying a thin film of DC-111
silicone grease (made by Dow-Corning) on the male pins prior to connection.
While probing with a voltmeter, take care not to short the probes. Shorts can damage
equipment, create safety hazards, and blow embedded fuses.
13.3 Deployment and Recovery Safety
Do not leave the sensor in direct sunlight. Extreme heat (35°C or greater) can cause
damage.
When deploying a sensor in water, do not leave it unattended. Boat drift can entangle
the cable and cause damage or sensor loss.
Never lift the sensor by pulling it from the cable. This can cause damage to the
bulkhead connectors, cables, and splices.
Dummy connectors should be replaced as soon as the equipment is retrieved. This will
help protect the bulkhead connector from dirt and damage.
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14. Warranty
14. Warranty
14.1 Warranty Period
All Satlantic equipment is covered under a one-year parts and labor warranty from date
of purchase.
14.2 Restrictions
Warranty does not apply to products that are deemed by Satlantic to be damaged by
misuse, abuse, accident, or modifications by the customer. The warranty is considered
void if any optical or mechanical housing is opened. In addition, the warranty is void if
the warranty seal is removed, broken or otherwise damaged.
14.3 Provisions
During the one year from date of purchase warranty period, Satlantic will replace or
repair, as deemed necessary, components that are defective, except as noted above,
without charge to the customer. This warranty does not include shipping charges to and
from Satlantic.
14.4 Returns
To return products to Satlantic, whether under warranty or not, contact the Satlantic
Customer Support Department and request a Returned Material Authorization (RMA)
number and provide shipping details.
All claims under warranty must be made promptly after occurrence of circumstances
giving rise thereto and must be received by Satlantic within the applicable warranty
period. Such claims should state clearly the product serial number, date of purchase
(and proof thereof) and a full description of the circumstances giving rise to the claim. All
replacement parts and/or products covered under the warranty period become the
property of Satlantic.
14.5 Liability
IF SATLANTIC EQUIPMENT SHOULD BE DEFECTIVE OR FAIL TO BE IN GOOD WORKING
ORDER THE CUSTOMER'S SOLE REMEDY SHALL BE REPAIR OR REPLACEMENT AS
STATED ABOVE. IN NO EVENT WILL SATLANTIC BE LIABLE FOR ANY DAMAGES,
INCLUDING LOSS OF PROFITS, LOSS OF SAVINGS OR OTHER INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING FROM THE USE OR INABILITY TO USE THE
EQUIPMENT OR COMPONENTS THEREOF.
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15. Contact Information
15. Contact Information
If you have any problems, questions, suggestions, or comments about the sensor or
manual, please contact us.
Call us direct at +1 902 492 4780 between 8 AM and 5 PM, Atlantic Time (GMT - 0400)
or send us an e-mail any time at [email protected]. For specific requests such as price
quotations, product support, or return materials authorization (RMA) for repair or
recalibration, please select the applicable contact:
Sales:
Support
Service:
http://satlantic.com/contact-sales or [email protected]
http://satlantic.com/contact-support or [email protected]
http://satlantic.com/rma
Written inquires and returns may be sent to:
Satlantic LP
Richmond Terminal- Pier 9
3481 North Marginal Road
Halifax NS B3K 5X8
CANADA
Satlantic is not open for business during Canadian statutory holidays:
New Year's Day
Good Friday
Victoria Day
Canada Day
Civic Holiday
Labor Day
Thanksgiving Day
Remembrance Day
Christmas Day
Boxing Day
January 1
The Friday before Easter Sunday
The first Monday before May 25
July 1
The first Monday in August
The first Monday in September
The second Monday in October
November 11
December 25
December 26
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16. Revision History
16. Revision History
Revision A, 2013-11-01:
Initial release.
Revision B, 2014-05-02:
3.2.3 Refer for T-S-Correction to SUNACom.
5.2 Expand data file type explanation.
7.1 Fix typo in frame table, nitrate units.
11.2. Remove external wiper; enlarge wiper images.
Revision C, 2014-05-15:
3.2.3 Add μM nitrate to mg/l nitrogen conversion factor.
Revision D, 2014-09-16:
3.2.1 Add storage and operating temperature range.
3.2.2 Add 1 A current requirement of power supply.
4.2.3 Add acquisition file type duration setting.
4.2.3 Add minimum interval for external device.
4.2.5 SDI-12 operation: wiper and internal logging.
5.4.1 Specify 1 PSU limit for freshwater processing.
Revision E, 2014-12-01:
4.2.1 Added special swipewiper command.
4.2.3 Remove unused legacy configuration parameters.
4.2.3 Add Custom Identification configuration parameter.
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